Process for making ingot-molds.



Unrann srnrns PATENT onn on CHARLES G. ROBINSON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 HARRY E. SHELDON, OF PITTSBURGH, PENNSYLVANIA.

PROCESS FOR MAKING INGOT-MOLDS.

Specification of Letters Patent. Patented July 18, 1916.

Application filed November 4, 1912. Serial N 0. 729,279.

To all whom it may concern:

Be it known that I, CHARLES G. ROBIN- SON, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Processes for Making Ingot-M'olds, of which the following is a specification.

My invention relates to methods for making ingot molds.

It is one of the objects of the present invention to improve the manufacture of steel ingot molds by the use of permanent steel molds, as distinguished from molds having impel-manent exterior walls and cores, composed of such material as molding sand, which has to be molded before each casting operation, the said mold to be used with a metallic core, preferably steel.

My invention comprises the method of making ingot molds whereby the said permanent core may be extracted from the ingot mold without injury to the ingot mold and without the ingot mold becoming shrunk upon the core.

The drawing shows in a central vertical section an apparatus for castingtwo ingot molds at a single pouring.

On the drawing, 1 represents a metallic horizontal base or stripper plate, which has two vertical openings, in which the vertical steel cores 2 fit. The cores extend upwardly at least to the top of the external steel wall 3 of the mold and have the staples 4 in a cavity in the top thereof, the top of the staples not extending above the top of the core. The mold wall 3 surrounds the core 2, a molding-space being left between them and having the shape and dimensions of the ingot mold to be cast. I show the moldingspace containing an ingot mold 5 cast therein. The molding-spaces are connected below by the runners 6 through which the molten metal for casting the ingot molds 5 runs from the gate 7, located between the two molds. The ingot molds 5 are shown with the staples 8 at their upper end and for use with ingot strippers. The cores 2 may be held in place in different ways by means applied to the top, the bottom, or both. I have shown the staples 4 to which a cable may be attached for hoisting the core to its place in the mold and for holding it there.

Supposing the mold walls and the cores to be in the position shown, the molten metal is poured into the gate 7, from which it runs through the runners 6 and into the bottom of the molding-space until the latter is filled to the top or the desired level. Shortly after the molding-space has been filled with the molten metal, the cores 2 are pushed down through the stripping plate 1, and into the pits 9 formed in the support for the stripping plate, the cores being shown by dotted lines in the pit. I have shown no mechanism for pushing the cores downwardly, but suitable mechanism can readily be designed for this purpose. The cores may be drawn downwardly by applying power to the staples, shown in dotted lines in the lower end of the cores.

It is not possible to fix a precise time limit for the extraction ofthe core. The temperature of the metal poured, the size of the casting, the thickness of the mold wall and the core, the temperature of the atmosphere, and various other conditions have their effect on the time when the casting reaches a definite condition. When steel is poured into a permanent mold, the tendency of the poured metal is, on striking the cold mold surfaces, to shrink away therefrom, the cast metal not beginning to contract on the core until after the center of the walls just cast begins to solidify and change from red to dark red. It is during this period of change that the extraction of the core should take place. The extraction of the core takes place after the casting has set and before, and preferably just before, it shrinks onto the core. By extracting the core during this period, the interior wall of the ingot mold is left smooth and the ingot mold can naturally shrink Without resistance or injury. By my apparatus, I am able to chill both the outer and inner surfaces of the ingot molds.

I claim 1. The process of making steel ingot molds which consists in pouring the molten metal for the ingot mold into a moldingspace and into contact with a steel core, allowing the cast metal to cool until the color extracting the core before the cast metal shrinks on the same.

Signed at Pittsburgh, Pa, this 2nd day of November, A. D. 1912.

CHARLES G. ROBINSON.

of its central portions begins to change to dark red, and then extracting the core.

2. The process of making steel ingot molds Which consists in pouring the molten metal for the ingot mold into a moldingspace and into contact With a steel core, al- Witnesses: lowing the cast metal to 0001 until 1t sets CLARA I. HoUs'roN, and 1ts inner surface forms a chill, and F. N. BARBER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

